(zilch magic): purposely dangle self-references in IA->CA handling

This is to workaround an issue I don't know how to fix right now.
In effect: Some of the Nix code contains the placeholder for $out,
which then gets translated to $out for that store path. Converting that
fails, for obvious reasons. However, rewriting those to self-references
is more complicated than I want to get into right now, and as the
behavior of self-references is vaguely broken (and this only affects
one test and a comment), I'm going to take the easy way out and make
it generate a dangling reference.

core/src/magic.sld

@@ -59,7 +59,7 @@
        ; It turns out these are broken in both Nix and Lix.
        ; Also, I now don't have to implement the _second_ type of modulo
        ; hash in Scheme, so that's a win for me.
-       (error "Refusing to import self-referenced CA path into the store.")
+       (fprintf (current-error-port) "Path ~S has self-reference, this will dangle!\n" path)
        (if (null? (cdr self-references))
          (set! references-filtered '())
          (begin
@@ -70,9 +70,9 @@
            (set-cdr! self-references (cddr self-references)))))
 
      (define name (string-copy path (+ (string-length (%store-dir)) 1 32 1)))
-     (define ca-store-path (make-fixed-output-with-references hash name references-filtered self-references))
+     (define ca-store-path (make-fixed-output-with-references hash name references-filtered #f))
      (unless (daemon-wop-query-path-info conn ca-store-path)
-       (daemon-wop-add-to-store-nar conn ca-store-path (valid-path-info-deriver data) (hex hash) references nar-size (string-append "fixed:r:sha256:" (as-base32 hash))
+       (daemon-wop-add-to-store-nar conn ca-store-path (valid-path-info-deriver data) (hex hash) references-filtered nar-size (string-append "fixed:r:sha256:" (as-base32 hash))
          (lambda (write-blob)
            (define new-conn (daemon-connect))
            (daemon-wop-nar-from-path new-conn path)